Abstracts III - Space and climate: adaptations of animals and humans

Climate change and responses of biological diversity: using amphibians as a model system

James Harris

CIBIO/UP, Centro de Investigação em Biodiversidade e Recursos Genéticos da Universidade do Porto, Campus Agrário de Vairão, Rua Padre Armando Quintas, 4485-661 Vairão, Portugal

Since the origin of life on earth, organisms have adapted to a constantly changing environment. Long before humans developed the idea that they are modifying climate due to their activities on the planet, climate change was the rule and not the exception. In particular, the Quaternary, a period that started about two million years ago, was characterized by regular and profound climatic changes due to the occurrence of glaciations which shaped patterns of biological diversity on Earth. For example, as recently as 20,000 years ago, the last glacial maximum resulted in the near absence of life in what we know today as Central and Northern Europe, whereas many organisms survived in the so-called southern refugia (the peninsulas of Iberia, Italy and the Balkans). Amphibians and reptiles are extremely suitable species to study the impact of climate change on biological diversity, both past and present, partly because they have a low dispersal rate, making them useful for tracking records of past and on-going climate modifications. In this presentation we describe our current knowledge on how past climate change shaped the distribution and genetic diversity of amphibian and reptile species with a special emphasis on the Iberian Peninsula. We show that Iberia is a unique place to study this topic because it is both a hotspot and a melting pot of genetic diversity. It is a hotspot because during extreme cold periods many species survived in the Peninsula and went extinct elsewhere. It is a melting pot because extreme oscillations resulted in fragmented populations that diverged and later contacted again. Today, central and southeastern Iberia are submitted to extreme arid conditions and offer a stressful environment to amphibians that should be monitored in order to investigate the impact of current climate and environmental change on biological diversity. This talk will be illustrated with our own on-going research work on Iberian herpetofauna.

Prehistoric and medieval mobile pastoral strategies: an archaeozoological perspective

Marta Moreno-García, Centro de Ciências Humanas y Sociales, Madrid

Carlos M. Pimenta, Instituto de Gestão do Património Arquitectónico e Arqueológico, Lisboa

Seasonal pastoral systems as transhumance have traditionally been interpreted as the ‘natural’ husbandry strategy to be followed in the Mediterranean world. Underlying this situation was the assumption that topographical relief and season were, if not totally determinant, primary factors in the emergence and development of mobile pastoral strategies. However with the increase in palaeoenvironmental studies, particularly pollen and charcoal analyses, this statement has become questionable. Since mountains in the Mediterranean are too low to grow alpine meadows, open summer grazing areas would not be a ‘natural’ feature of this landscape. Upland pastures can be considered mainly the product of human interference, either by fire and axe or through grazing (Mellars, 1976; Forbes & Koster,1976). Before extensive clearance took place, accessibility to and herding in woodland pastures during the summers may be assumed to have been difficult and given the fact that there existed wooded zones in the lowlands, may be unnecessary. Thus, it appears that the role played by environmental conditions in the emergence of seasonal mobile pastoral systems in this geographical area could have been more secondary than initially thought.

Studies among traditional Mediterranean pastoral communities (i.e.: Lewthwaite, 1983; Barker & Grant, 1991) have shown that periodical movements of livestock offer the possibility of maintaining larger populations during those seasons when local grazing resources are scarce. Consequently, physical conditions of a geographical area regarding grazing availability must be considered together with the scale at which livestock might have been kept. Both variables are linked. Equally valuable and closely related to them is the question of the extension of the territory exploited. Intra- or extra-regional movements could distinguish transhumance from other mobile pastoral systems. Finally, it cannot be forgotten that all these issues are associated with the level of productivity pursued by the shepherds.

The aim of this paper is to discuss the possibilities offered by the analysis and study of domestic faunal remains from archaeological sites to explore some of the issues just mentioned. Two case studies are presented. Firstly, the faunal sample recovered from the cave of Els Trocs dated to the Neolithic and located in the Spanish Pyrenees. Secondly, the faunal assemblage from Albarracín Castle (Teruel) dated to the medieval period. The estimation of kill-off patterns noting the absence or presence of particular age groups and the recognition of lambing and killing seasons are data analysed which may help to recognise the pastoral systems followed by these two upland human communities.

References:

Barker, G. & Grant, A. (eds.) (1991). Ancient and modern pastoralism in Central Italy: an interdisciplinary study in the Cicolano Mountains. Papers of the British School at Rome 59, 15-88.

Forbes, H.A. & Koster, H.A. (1976). Fire, axe, and plow: human influence on local plant communities in the Southern Argolid. In (M. Dimen & E. Friedl, eds.) Regional variation in modern Greece and Cyprus: toward a perspective on the ethnography of Greece. Annals of the New York Academy of Sciences 268, 109-126.

Lewthwaite, J. (1983). The art of coarse herding: archaeological insights from recent pastoral practices on west Mediterranean islands. In (J. Clutton-Brock & C. Grigson, eds.) Animals and Archaeology 3. Early herders and their flocks. Oxford: BAR International Series 202, pp. 25-37.

Mellars, P. (1976). Fire ecology, animal populations and man: a study of some ecological relationships in prehistory. Proceedings of the Prehistoric Society 42, 15-45.